Computer systems, particularly servers, utilize memory devices that are known to be less reliable than would be desirable. Various reliability features have been developed to address this known unreliability. Generically, these features may be referred to as reliability, availability and serviceability (RAS) features. Rank sparing and double device data correction (DDDC) are examples of RAS features.
Rank sparing requires that a whole rank of memory be held in reserve to cover for a failed device in the future. This can be wasteful of system resources. DDDC typically requires lockstepping, which requires high power consumption and reduced bandwidth. Thus, current RAS features are not particularly resource-efficient.